Molecule structure of Endothion (CAS NO.2778-04-3) :

IUPAC Name: 2-(dimethoxyphosphorylsulfanylmethyl)-5-methoxypyran-4-one 
Molecular Weight: 280.234681 g/mol
Molecular Formula: C₉H₁₃O₆PS 
Density: 1.35 g/cm³ 
Boiling Point: 411.3 °C at 760 mmHg 
Flash Point: 202.5 °C
Index of Refraction: 1.518
Molar Refractivity: 62.87 cm³
Molar Volume: 207.2 cm³
Polarizability: 24.92*10^-24 cm³
Surface Tension: 45.7 dyne/cm 
Enthalpy of Vaporization: 66.37 kJ/mol 
log P (octanol-water): -0.310
Water Solubility: 1.50E+06 mg/L
Vapor Pressure: 5.69E-06 mm Hg
Henry's Law Constant: 6.46E-12 atm-m³/mole 
Atmospheric OH Rate Constant: 9.55E-11 cm³/molecule-sec
XLogP3-AA: -0.2
H-Bond Acceptor: 6
Rotatable Bond Count: 6
Exact Mass: 280.017045
MonoIsotopic Mass: 280.017045
Topological Polar Surface Area: 71.1
Heavy Atom Count: 17
Complexity: 394
Canonical SMILES: COC1=COC(=CC1=O)CSP(=O)(OC)OC
InChI: InChI=1S/C9H13O6PS/c1-12-9-5-15-7(4-8(9)10)6-17-16(11,13-2)14-3/h4-5H,6H2,1-3H3
InChIKey: YCAGGFXSFQFVQL-UHFFFAOYSA-N
EINECS: 220-472-3

 Endothion (CAS NO.2778-04-3) is used as an insecticide. Not sold in the USA or Canada.

EPA Extremely Hazardous Substances List.

A poison by ingestion and skin contact. A pesticide. When heated to decomposition it emits very toxic fumes of PO_x and SO_x.
Hazard Codes: T
Risk Statements: 24/25 
R24: Toxic in contact with skin 
R25: Toxic if swallowed
Safety Statements: 36/37-45 
S36/37: Wear suitable protective clothing and gloves 
S45: In case of accident or if you feel unwell, seek medical advice immediately (show the label whenever possible)
RIDADR: 2783
HazardClass: 6.1(a)
PackingGroup: II

 Endothion (CAS NO.2778-04-3) is also called 4-18-00-01160 (Beilstein Handbook Reference) ; 5-Methoxy-2-(dimethoxyphosphinylthiomethyl) pyrone-4 ; AI3-24653 ; BRN 0252435 ; ENT 24,653 ; EPA Pesticide Chemical Code 422100 ; Niagara 5767 ; O,O-Dimethyl S-(5-methoxy-4-oxo-4H-pyran-2-yl) phosphorothioate ; O,O-Dimethyl phosphorothioate S-ester with 2-(mercaptomethyl)-5-methoxy-4H-pyran-4-one ; O,O-Dimethyl-S-((5-methoxy-pyron-2-yl)-methyl)-thiolphosphat Phosphopyrone ; Phosphorothioic acid, O,O-dimethyl ester, S-ester with 2-(mercaptomethyl)-5-methoxy-4H-pyran-4-one ; S-5-Methoxy-4-pyron-2-ylmethyl O,O-dimethyl phosphorothioate ; Thiophosphate de O,O-dimethyle et de S-((5-methoxy-4-pyronyl)-methyle) . Endothion (CAS NO.2778-04-3) is white crystals with a slight odor.
Organothiophosphates, such as endothion, are susceptible to formation of highly toxic and flammable phosphine gas in the presence of strong reducing agents such as hydrides. Partial oxidation by oxidizing agents may result in the release of toxic phosphorus oxides. Endothion is poisonous to humans. Its toxic effects are most likely related to action on the nervous system. Cylinder may explode in heat or fire. Fire and runoff from fire control water may produce irritating or poisonous gases. When heated to decomposition, endothion emits very toxic fumes of phosphorous oxides and sulfur oxides. So the storage environment should be ventilate, low-temperature and dry. Keep Endothion (CAS NO.2778-04-3) separate from raw materials of food.